Temperature-pressure transducer

ABSTRACT

In the present invention, a pair of outlet channels are coupled directly to a relatively low pressure source and through a pair of thermostatically-controlled valves are also coupled to a relatively high pressure source. Only one or the other of the valves is open at any one time. Accordingly, when the transducer is in a relatively cool environment, one outlet channel will have the high pressure in it and the other outlet channel will have the low perssure in it. On the other hand, when the transducer environment is relatively warm, the pressures in the two outlet channels are reversed. The valves governing the pressures in the outlet channels are opened and closed in response to the motion of a coiled bi-metallic strip and, consequently, are opened and closed in response to the ambient temperature conditions.

United States Patent [191 Osheroff [451 June 5, 1973 2,155,796 4/1939 Mayner 0236/40 of a coiled bi-metallic strip and, consequently, are 2,242,649 5/1941 Leonard ..236/12 opened and closed in response to the ambient tem-- 2,596,366 5/1952 Brockett ..236/48 A perature conditions. 3,172,600 3/1965 Miner 236/81 X 1,312,253 8/1919 Johnson ..236/87 8 Claims, 3 Drawing Figures 2.40. 22b 2! \Qib 25b 25a 2 lo lOa/ TEMPERATURE-PRESSURE TRANSDUCER Gene W. Osheroff, Las Vegas, Nev.

Fluidtech Corporation, Inglewood, Calif.

Dec. 7, 1971 205,503

Inventor:

Assignee:

Filed:

Appl. No.:

References Cited UNITED STATES PATENTS Primary Examiner-William E. Wayner AttorneyAllen E. Botney [57] ABSTRACT In the present invention, a pair of outlet channels are coupled directly to a relatively low pressure source and through a pair of thermostatically-controlled valves are also coupled to a relatively high pressure source. Only one or the other of the valves is open at any one time. Accordingly, when the transducer is in a relatively cool environment, one outlet channel will have the high pressure in it and the other outlet channel will have the low perssure in it. On the other hand, when the transducer environment isrelatively warm, the pressures in the two outlet channels are reversed. The valves governing the pressures in the outlet channels are opened and closed in response to the motion TEMPERATURE-PRESSURE TRANSDUCER The present invention relates to transducers in general and more particularly relates to a temperaturepressure transducer.

It is frequently necessary in the technological arts to determine whether an environment is relatively hot or cold and then to translate that information into corresponding gas-pressure signals. In the field of airconditioning, for example, it is necessary in some systems to know whether the conditioned air flowing in the supply duct is hot or cold and, once this determination is made, to adapt the system for such flow. More specifically, if a system which has been operating in the cooling mode is then thrust into the heating mode or vise versa, it may be necessary to operate one or more control mechanisms in order to adjust the system to this change in mode. Of course, the signals used to operate such control mechanisms will depend, primarily, on the kind of control mechanism employed and, therefore, in some systems, at least the signals will be of the gaspressure variety.

It is, therefore, an object of the present invention to provide a transducer capable of translating temperature differentials to pressure differentials.

It is another object of the present invention to provide a transducer that is operable to produce pressure signals in response to marked changes in ambient temperature conditions.

It is a further object of the present invention to provide a transducer capable of translating a relatively warm ambient environment into one type of pressure signal and a relatively cool ambient environment into another type of pressure signal.

It is an additional object of the present invention to provide a transducer that can detect whether an airconditioning system is operating in the cooling or heating mode and, in response thereto, produce gaspressure signals that respectively correspond to said modes.

The novel features which are believed to be charactertistic of the invention, both as to its organization and method of operation together with further objects and advantages thereof, will be better understood from the following description considered in connection with the accompanying drawing in which an embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purpose of illustration and description only and is not intended as a definition of the limits of the invention.

FIG. 1 is a front view of a preferred embodiment of a temperature-pressure tranducer according to the present invention;

FIG. 2 is a top view of the same embodiment; and

FIG. 3 is a side view of the embodiment.

For a consideration of the invention in detail, reference is now made to the figures in the drawing wherein an embodiment of the present invention is shown to preferably include a pair of members a and 10b through which a pair of channels 11a and 11b respectively extend. If necessary, tubing may respectively be coupled to the input and output ports of channels 1 1a and 11b as shown in the figures, the tubes coupled to the input ports being designated 12a and 12b and the tubes coupled to the output ports being designated 13a and 13b. Tubes 12a and 12b are coupled to a relatively low pressure source (not shown), whereas tubes 13a and 13b are coupled to whatever mechanism is to be controlled by the transducer. To rigidly mount and hold members 100 and 10b in place, the embodiment also includes a pair of cross bars or members 14 and 15 to which members 10a and 10b are cemented or otherwise fastened, with the result that all 'four members form a rigid unit.

Rotatably mounted between cross members -14-and 15 is a shaft 16, the ends of the shaft extending into these members as shown in the figures. A coiled ibimetallic strip 17 is mounted on shaft 16, the center of the coil being rigidly fastened to the shaft so that in the event of any rotative movement of the coil, the coil and the shaft will rotate together. Theother end of the coil, designated 17a, extends from the body of the coil to member 10b where it is fixed in position just above the member by means of a nail or screw 18 which passes through end 17a and into member 10b. A spring 20 is mounted on the nail or screw between end 17a and member 10b, the spring forcing the coil end up against the head of the nail or screw and thereby preventing it from easily moving up and down.

Respectively connecting with channels 11a and 11b are a pair of identical valves, generally designated 21 and 22, that comprise a pair of passageways or channels 21a and 22a and a plate or bar 23 that is rigidly mounted in see-saw fashion on shaft 16. For reasons that will be seen later, plate or bar 23 is made of a magnetizable material. Channels 21a and 22a respectively extend downward from the top surfaces of members 10a and 10b until they connect or couple with channels 11a and lltherein, the ends of plates 23, respectively designated 23a and 23b, extending or lying over the entrances or openings to channels 21a and 22a. In order to ensure an affirmative and effective opening and closing action for valves 21 and 22, there is preferably also provided, first, a pair of circular lips 21b and 22that are respectively mounted on the surfaces of members 10a and 10b around the openings to channels 210 and 22a and, second, a pair of felt pads 24a and 24b respectively mounted on the underside of plate or bar ends 23a and 23b. As shown in the figures, pads 24a and 24b respectively overlie lips 21b and 22b and effectively cover the openings to channels 2la'and22a when they are brought into contact with these lips. I

At this point, it would be well to mention that several things can be done and, preferably, are done to obtain a speedy response from valves 21 and 22 and, therefore, from the transducer itself. First, the load on coil 17 is reduced to a minimum and this can be achieved by keeping the weight of plate 23 and pads 24 to a practical minimum. This, in turn, can be achieved by choosing materials of relatively light weight for them and by keeping their thicknesses to a practical minimum. Secand, the spacing between the pads and the lips are made as small as possible. Third, the distance through which the ends of plate 23 travel are also kept as small as possible, that is to say, to within necessary limits only, and this is done by providing another pair of lips 25a and 25b on the top surfaces of members 10:; and 10b, respectively, preferably at the outer edges thereof, against which the ends of plate 23 respectively abut as one or the other of the valves is closed.

Finally, a preferred embodiment of the present invention also includes a pair of magnets 26a and 26!: mounted on a cross bar 27. Magnets 26a and 26b are mounted beneath plate or bar 23 intermediate shaft 16 and members 100 and 1012, the primary purposes or functions of the magnets being, first, to bias plate or bar 23 to ensure that one or the other of the valves will at all times be closed and, second, to apply slight restraining forces on the plate or bar that will cause the valves to open and close at slightly different temperatures, thereby helping to avoid spurious openings and closings due to slight fluctuations in temperature that may occur about the set points of the valves. By set point is meant the temperature at which each valve is designed to close. By way of example, if valve 22 is designed to close and valve 21 to open at 76 degrees Fahrenheit and valve 21 is designed to close and valve 22 to open at 74 Fahrenheit, then 76 and 74 are respectively the set points for these valves and the temperatures therebetween form what may be termed a dead band in which the states or conditions of the valves are not affected. Thus, if valve 22 is closed, which means valve 21 is open, then a momentary fluctuation of the ambient temperature to 76 Fahrenheit will not affect the situation and valve 22 will remain closed. The same is true if valve 21 is closed and valve 22 open. It will be recognized by those skilled in the art that by suitable design, the set points can be brought further together or apart, as desired.

In considering the operation of this transducer, it will be assumed that it is located in a relatively high pressure environment and that tubes 12a and 12b extend therefrom and couple to a relatively low pressure environment. Thus, through valves 21 and 22, channels 11a and 11b are respectively exposed to a relatively high gas pressure and through tubes 12a and 12b to a relatively low gas pressure. It will also be initially assumed, that the ambient temperature is high enough so that valve 22 is closed, with the result that the output signal produced by the transducer comprises a high pressure in output tube 13a and a low pressure in output tube 13b. This is so because with valve 22 closed, the high pressure of the ambient environment cannot get through to channel 11b and from there to output tube 13b. Of course, the reverse is true on the other side of the transducer where valve 21 is open.

If, now, the temperature of the environment in which the transducer is located drops to the set point of valve 21 or below, bi-metallic coil will contract sufficiently to rotate shaft 16 and, therefore, plate 23, in a counterclockwise direction to thereby close valve 21 and, simultaneously therewith, open valve 22. When this occurs, the output signal produced by the transducer then comprises a low pressure in output tube 13a and a high pressure in output tube 13b, just the reverse of the earlier signal.

The transducer will return to its former state if the ambient temperature should rise to at least the set point of valve 22. Under such circumstances, bi-metallic coil 17 will expand and thereby enter into a clockwise rotational movement which, when the set point is reached, causes shaft 16 and, therefore, plate 23 to likewise rotate in a clockwise direction. With the clockwise rotation of plate 23, valve 22 is thereby closed and, simultaneously therewith, valve 21 is opened. At this point, the output signal is again a highpressure in output tube 13a and a low pressure in output tube 13b.

Although a particular arrangement of the invention has been illustrated above and described herein by way of example, it is not intended that the invention be limited thereto. Accordingly, the invention should be considered to include any and all modifications, alterations or equivalent arrangements falling within the scope of the annexed claims.

Having thus described the invention, what is claimed l. A temperature-pressure transducer by means of which one or the other of two different pressure combinations is produced at the output end thereof in response to ambient temperature conditions, said apparatus comprising: means having first and second channels extending therethrough, said first and second channels respectively having first and second input ends and first and second output ends; first and second valves respectively coupled to said first and second channels intermediate their said ends; first and second pressure sources, said first pressure source being coupled to the input ends of both said first and second channels and said second pressure source being coupled to both said first and second valves; and temperature-responsive means for simultaneously closing one and opening the other of said valves to produce one or the other of the pressure combinations.

2. The transducer defined in claim 1 wherein said temperature-responsive means includes a rotatably mounted shaft; a member mounted on said shaft and rotatable therewith, said member being adapted to simultaneously close one and open the other of said valves in response to rotation of said shaft; and a coiled bimetallic strip copupled to rotate said shaft in clockwise and counterclockwise directions in response to changes in temperature.

3. The transducer defined in claim 1 wherein said temperature-responsible means includes a coiled bimetallic element mounted to move in clockwise and counterclockwise directions in response to changes in temperatures, and apparatus coupled between said bimetallic element and said valves, said apparatus being operable when said element moves in a clockwise direction to open and close said'first and second valves, respectively, and operable when said element moves in a counterclockwise direction to close and open said first and second valves, respectively.

4. The transducer defined in claim 2 wherein said member is made of a magnetizable material and wherein the transducer further includes a pair of magnets mounted beneath said member intermediate said shaft and valves.

5. The transducer defined in claim 2 wherein said first and second valves respectively include first and second passageways that respectively connect with said first and second channels, and wherein the transducer includes additional means cooperating with said member for closing one entrance to said passageway at a time.

6. That transducer defined in claim 3 wherein said apparatus includes a shaft rotatably mounted between said valves and coupled to said bi-metallic element to rotate with the movement therewith; and a plate mounted in see-saw fashion on said shaft and extending over said valves, said plate rotating with said shaft to close one and open the other of said valves. I

7. The transducer defined in claim 5 wherein said member is a plate mounted in see-saw fashion on said shaft and extending over said passageways and wherein said additional means includes felt-like pads respectively mounted on the ends of said plate on the underside thereof to cover the entrances to said passageways the transducer further includes a pair of magnets when moved by said plate into contact therewith, mounted beneath and in proximity to said plate inter- 8. The transducer defined in claim 7 wherein said mediate said shaft and said valves. plate is made of a megnatizable material and wherein 

1. A temperature-pressure transducer by means of which one or the other of two different pressure combinations is produced at the output end thereof in response to ambient temperature conditions, said apparatus comprising: means having first and second channels extending therethrough, said first and second channels respectively having first and second input ends and first and second output ends; first and second valves respectively coupled to said first and second channels intermediate their said ends; first and second pressure sources, said first pressure source being coupled to the input ends of both said first and second channels and said second pressure source being coupled to both said first and second valves; and temperature-responsive means for simultaneously closing one and opening the other of said valves to produce one or the other of the pressure combinations.
 2. The transducer defined in claim 1 wherein said temperature-responsive means includes a rotatably mounted shaft; a member mounted on said shaft and rotatable therewith, said member being adapted to simultaneously close one and open the other of said valves in response to rotation of said shaft; and a coiled bimetallic strip copupled to rotate said shaft in clockwise and counterclockwise directions in response to changes in temperature.
 3. The transducer defined in claim 1 wherein said temperature-responsible means includes a coiled bi-metallic element mounted to move in clockwise and counterclockwise directions in response to changes in temperatures, and apparatus coupled between said bi-metallic element and said valves, said apparatus being operable when said element moves in a clockwise direction to open and close said first and second valves, respectively, and operable when said element moves in a counterclockwise direction to close and open said first and second valves, respectively.
 4. The transducer defined in claim 2 wherein said member is made of a magnetizable material and wherein the transducer further includes a pair of magnets mounted beneath said member intermediate said shaft and valves.
 5. The transducer defined in claim 2 wherein said first and second valves respectively include first and second passageways that respectively connect with said first and second channels, and wherein the transducer includes additional means cooperating with said member for closing one entrance to said passageway at a time.
 6. That transducer defined in claim 3 wherein said apparatus includes a shaft rotatably mounted between said valves and coupled to said bi-metallic element to rotate with the movement therewith; and a plate mounted in see-saw fashion on said shaft and extending over said valves, said plate rotating with said shaft to close one and open the other of said valves.
 7. The transducer defined in claim 5 wherein said member is a plate mounted in see-saw fashion on said shaft and extending over said passageways and wherein said additional means includes felt-like pads respectively mounted on the ends of said plate on the underside thereof to cover the entrances to said passageways when moved by said plate into contact therewith.
 8. The transducer defined in claim 7 wherein said plate is made of a megnatizable material and wherein the transducer further includes a pair of magnets mounted beneath and in proximity to said plate intermediate said shaft and said valves. 